Understanding phantom particle counts

18 May, 2021

The S120 digital imaging particle counter can recognise solid particles and summarize them into 4, 6, 14, 21, 38, 70 and >100 micron ranges. It can also recognise shapes and give individual shape recognition counts as sliding, cutting and fatigue wear particles. Bubbles are also recognised and removed from the counts.

Therefore, digital imaging particle counting technology can negate the micelle-like antifoaming additive encapsulations as water droplets – phantom particles – allowing users to understand the condition of their fluids with confidence. Two case studies demonstrate how the Particle Pal Pro a fluid condition monitoring solution with digital imaging particle counting technology, can overcome phantom particle counting.

Laser vs digital imaging particle counter test

In a lab-based test conducted on base oil with no additives, Filtertechnik ran 2 particle counters feeding from the same oil warmed to 40degC. A PC9001 laser counter and an S120 digital imaging particle counter. Filtertechnik then dosed in exactly 100ppm polydimethylsiloxane anti foaming additive. The results were immediately apparent in the laser counter, affecting the 4 and 6 micron counts by up to 3 ISO codes, the 14 micron count slightly less so, but still an increase of 1 ISO code. The digital imaging counter remained unaffected by the additive.

Particle Pal Pro

The Particle Pal Pro is equipped with the S120 digital imaging particle counter and, together with water and oil degradation sensors, delivers a powerful on-site oil analysis instrument. Advanced software reports all the readings in a clear, easy-to-read format. Long term trending of assets is built in, as well as image capture of contamination for reporting purposes.

● New Digital imaging particle counting gives broad micron counts

4, 6, 14, 21, 38, 70 and >100 microns 

ISO, NAS, SAE counts

Shape recognition

Particles are categorised as Sliding, Cutting and Fatigue Wear as well as Fibres

Air bubbles are counted and removed from the counts

● High resolution images are stored for reporting

Particles can be sized on the screen via the software to aid reporting

● The ability to self-prime, pump and measure oil up to 2,400cst

● Self-contained unit with battery and internal stepper motor pump

Accessory case with measurement flasks, vacuum thief pump etc. included

● Additional sensors included:

Water sensing %RH (tracked against temperature)

Remaining life of the oil via a TanDelta sensor

● A database of over 500 oils are included with calibrated degradation curves

Ability to self-calibrate any oil not on the database

● Export data to .xls, pdf and .jpg for the images collected

Case study

An OEM of large off-highway equipment was experiencing continuous particle counter inaccuracies at a verification stage of assembly. The rejections due to fluid condition were mounting, causing delayed shipments and significant related costs. The average holding time delay due to rejection was seven days, which incurred a holding cost of £1000-a-day per unit. At the consultation phase of the case study, eight units had been delayed.

The diagnosis was in: the existing laser light-blockage-type particle counters were providing inconsistently high and erroneous particle counts. The ISO 4406 cleanliness would frequently measure 23/22/19, despite a strong fluid-maintenance and conditioning regime. Third-party fluid analysis reports and fluid datasheets suggested that the synthetic hydraulic fluid contained a high concentration of a siloxane (silicone derivative) antifoaming additive, known to cause phantom particle measurements in LBM automatic particle counters.

Filtertechnik provided an extensive on-site demonstration that proved the advanced digital imaging technology of the Particle Pal Pro portable fluid contamination monitoring solution, which measured an average ISO fluid cleanliness of 15/14/10. This allowed the customer to successfully process the fluid and pass six units during the first day of demonstration. The two remaining backlogged units passed early on the second day of demonstration. The savings evidenced by the demonstration equated to approximately 35% in cost savings and an 81% reduction in holding time.

For more information:

www.filtertechnik.co.uk

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